1. Technical Field
The present invention relates to recording apparatuses.
2. Related Art
Some recording apparatuses record images onto a roll member medium (for example, “roll paper”) onto which is wrapped a band-shaped. Roll members used in large-format recording apparatuses are heavy, and produce a significant load when pulling out and transporting the paper. For this reason, there is a risk of the paper tearing if the paper is taken out and transported using only the driving force of a transport unit (for example, a “transport roller”). Accordingly, an apparatus has been proposed in which a roll motor for rotationally driving a roll member is provided and the paper is transported by driving the transport roller and by also driving the roll motor.
Meanwhile, the load when taking out and transporting the paper decreases as the roll member continues to be used. Accordingly, if the paper is always transported at a constant driving force, there is a risk that the paper will loosen between the transport roller and the roll member. Accordingly, a method has been proposed that measures a load when supplying a roll member when the driving of a transport roller is stopped (that is, a load exerted on a roll motor) and controls the driving of the roll motor based on the result of the measurement, so that a predetermined tension is always applied to the paper.
JP-A-2009-242048 is an example of the related art.
However, because roll members used in large-format recording apparatuses are heavy, if, for example, the roll member is set in the apparatus and left for a long period of time, there is a risk that the central area of the roll member in the axial direction thereof will sag under its own weight. If this occurs, the center of gravity of the roll member will deviate from the rotational center, and the load will fluctuate significantly during each rotation of the roll member. In other words, the load will fluctuate depending on the angle of the roll member. If the roll member is nevertheless only rotated a small amount (for example, only ¼ rotation) when measuring the load, there is the risk that a skewed value will be measured for the load. On the other hand, if the roll member is greatly rotated all at once (for example, one full rotation) when measuring the load, the paper will sag significantly around the roll member. If this occurs, there is a risk that the areas of the sagging paper will make contact with peripheral members and the paper will be damaged as a result.